I have a question here

 

A rectangular plane loop with dimensions 250 mm by 180 mm is pivoted to rotate about the z axis. The long side of the loop is along the y-axis and the plane of the loop makes an angle of 45 degrees with the y-axis. If a uniform magnetic field of magnitude 300 mT is in the y direction: (a) Determine the magnitude and direction of the force of each side of the loop. (b) Determine the torque about the z axis.

 

I know that F=BILsin theta and Torque=BAIsin theta my problem here is how to get the current I

You would need to determine that. You could choose different currents and see what effect they have on the results, or you could get a value for the force or torque and use that to determine the current. Your third choice is to plug in values for what you know and look at the relation between torque and current for this specific example. Any way you do it, you need more information to get an actual answer.